1. Field of the Invention
The present invention relates to a deaerating method and deaerating apparatus for removing air from the inside of a bag that is filled with contents which is a liquid matter or with contents that contain a liquid matter.
2. Prior Art
Japanese Patent Nos. 3016052 (corresponding to Japanese Patent Application Laid-Open No. 7-2233) and 3138916 (corresponding to Japanese Patent Application Laid-Open No. 10-181713) disclose a deaerating method and apparatus for removing air from the insides of bags that are filled with a liquid matter or with contents that contain a liquid matter.
In the methods and apparatuses of these prior art patents, a suction nozzle that communicates with a vacuum source is inserted into a bag though its mouth, and air and excess liquid matter inside the bag are sucked out by the suction nozzle. In other words, in these prior art, the suction nozzle is inserted into the interior of the bag. Accordingly, there is a danger that contents adhering to the inside of the suction nozzle and coating material peeling from the surface of the suction nozzle (ordinarily, the surface of the suction nozzle is coated with Teflon (trademark) for the purpose of preventing the adhesion of contents) would be admixed with the contents inside the bag. This is an extremely important problem from the standpoint of hygiene in cases where the contents are foodstuffs.
Japanese Patent No. 2805378 (corresponding to Japanese Patent Application Laid-Open No. 4-44927) discloses an apparatus that fills packages under deaerated conditions.
In this apparatus, an area below the intended sealing position of the mouth of a bag is held by a chamber that has a pair of jaw-shaped members formed with air passage grooves. A vacuum is applied to the interior of the chamber so that the air inside the bag is sucked out through the air passage grooves, and then a sealing bar disposed inside the chamber is then actuated so as to seal the intended sealing position. However, if excess liquid matter inside the bag is sucked out together with the air from the locations of the air passage grooves, this liquid matter escapes through the locations of the air passage grooves inside the chamber and spreads throughout the entire intended sealing position, and it further overflows from the mouth of the bag and enters the interior of the chamber. The cleaning away of liquid matter that has overflowed into the interior of the chamber is cumbersome and time-consuming due to the complexity of the structure involved.
In any of the above-described systems, the adhesion and retention of liquid matter in the intended sealing position of the mouth of a bag is unavoidable, and this liquid matter enters the seal, leading to defective sealing. More specifically, in the case of the system that uses a suction nozzle described above, the liquid matter sucked out by the suction nozzle would remain in the location in the mouth of the bag where the suction nozzle was present, so that this liquid matter enters the seal when sealing is performed. In the case of the system that uses a chamber comprising jaw-shaped members described above, liquid matter adhering to the entire sealing position and liquid matter in the locations of the air passage grooves remains in the seal of the mouth during sealing.